P1322: ALLOGENEIC HEMATOPOIETIC STEM TRANSPLANTATION (HSCT) IN PATIENTS OVER 60 YEARS. RETROSPECTIVE EXPERIENCE OF TWO SPANISH CENTERS BETWEEN 2015-2020
Authors: M. Baile González, M. Hidalgo Soto, S. Marcos Asensio, M. Cabrero Calvo, R. Martínez Fernández, A. Avendaño Pita, A. Á. Martín López, A. Cabero Martínez, M. Cortés Rodríguez, E. Pérez López, L. López Corral, F. Sánchez Guijo, L. Vázquez López, M. D. Caballero Barrigón
Journal: HemaSphere (2022)

Background: The improvement in support treatment and the implementation of reduced intensity conditioning (RIC) makes that Allogeneic-HSCT in patients over 60 years is a standard clinical practice. Aims: To describe the results in overall survival (OS), progression-free survival (PFS), mortality and treatment-related mortality (TRM), and the factors involved in them. Methods: Retrospective study of 142 patients over 60 years with hematological neoplasms undergoing allogeneic HSCT. Results: Median age was 64 years, 8% were over 70 years old and 68% were male. 86% had positive CMV serology with donor/patient discrepancy in 18.5%. According to HCT-CI index, 27% were at high risk and with the HCT-CI-age, 5.5% were at very high risk. The principal indications (69.5%) were Acute Myeloblastic Leukemia and Myelodysplastic Syndrome and the median time from diagnosis to transplant was 7 months. 37% received HSCT with active disease and according to DRI-index, 27% were high or very high risk. The hematopoietic source was peripheral blood in all cases. 48% undergoing a related donor trasplant and 33%, haploidentical and in 90%, RIC regimens was used. Immunosuppression regimen was determined by the intensity of conditioning and donor type and the two most used were Tacrolimus/Sirolimus (43%) and Tacrolimus/Mycophenolate Mofetil/Cyclophosphamide post- transplant (34.5%). Median number of days of hospitalization was 30 and 93% had an optimal graft with a median of 17 days. The relapse/progression and mortality rate was 35% and 51%, respectively. Both events occurred more frequently in the first year after transplant (78% of relapses and 68% of deaths). With a median follow-up of 16.5 months from infusion, PFS was 43% (median 19 months) and OS was 49% (median 34 months). The first cause of death was relapse/progression (24.5%) and TRM was 22.5% (2nd cause of death). Within this, Graft Versus Host Disease and related infections were the predominant cause (65.5%) and globally were the 3rd cause of death (15%). Factors involved in OS and TRM are in Image 1. Diagnosis of chronic myeloproliferative disease, the donor/patient CMV serological discrepancy and undergoing unrelated trasplant with MAC regimen have unfavorable impact in OS. Although not significant, age >65 years, scoring high-risk in prognostic index (HCT-CI and DRI) were also associated with worse OS. Active disease at transplant did not have an apparent impact. No significant differences were observed in PFS. Higher relapse was observed in related recipients transplant (47%; p-value 0.04) and in patients with high and very high risk in DRI-index (54.5 and 60% respectively; p-value 0.001). Age was not related to a higher risk of relapse or worse PFS. A higher TRM was observed in haploidentical and unrelated trasplant compared with related donor (specially if RIC regimen). There were no differences with age, disease status to HSCT, and prognostic indexs. The specific modality of transplant (donor and conditioning intensity) maintained impact in the multivariate analysis. Non CR or progression at +100 day and early relapse (< 12 months) had a very negative impact on OS (median of 9 months: Non CR/progression p-value < 0.001/ HR 3, 3 (CI 1.9-6); early relapse p-value <0.001/HR 8.7 (CI 4.8-16.4). Image:Summary/Conclusion: Allogeneic HSCT in patients over 60 years achieves comparable results to younger patients with an acceptable TRM. The absence of response at day +100 and early relapsed have a wrong prognosis. Related donor trasplant with RIC regimen seems the best option dice less toxicity although comparative studies are necessary to confirm these results.